Dignitas don't learn. Their mid to b was poor, and they were putting 1 on B. When they put 2 there they stopped it. On 15-11, 4v4, you don't put 1 on B, 2 short (!!!!) and 1 CT spawn. If anything, put 2B, 1 CT and 1 short.
Also, don't push long as CT. They were always pushing up JW, and he was always getting a kill. When they smoked it off, Fnatic didn't get the kill. Putting 2 people on long not only increases the chances of a hit, but also leaves the other guy vulnerable for a 3/4/5 v 1 push.
Dust 2 was Dig's pick. Next map is overpass. Can be 2-0 for Fnatic tbh.
EDIT: Again, Dig never catered for olofm's flank. He did some 3 times in a row, one of them after an eco.That, and the lack of map familiarity have let them down on T side.